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Chen J, Rodriguez AS, Morales MA, Fang X. Autophagy Modulation and Its Implications on Glioblastoma Treatment. Curr Issues Mol Biol 2023; 45:8687-8703. [PMID: 37998723 PMCID: PMC10670099 DOI: 10.3390/cimb45110546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/26/2023] [Accepted: 10/26/2023] [Indexed: 11/25/2023] Open
Abstract
Autophagy is a vital cellular process that functions to degrade and recycle damaged organelles into basic metabolites. This allows a cell to adapt to a diverse range of challenging conditions. Autophagy assists in maintaining homeostasis, and it is tightly regulated by the cell. The disruption of autophagy has been associated with many diseases, such as neurodegenerative disorders and cancer. This review will center its discussion on providing an in-depth analysis of the current molecular understanding of autophagy and its relevance to brain tumors. We will delve into the current literature regarding the role of autophagy in glioma pathogenesis by exploring the major pathways of JAK2/STAT3 and PI3K/AKT/mTOR and summarizing the current therapeutic interventions and strategies for glioma treatment. These treatments will be evaluated on their potential for autophagy induction and the challenges associated with their utilization. By understanding the mechanism of autophagy, clinical applications for future therapeutics in treating gliomas can be better targeted.
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Affiliation(s)
- Johnny Chen
- Department of Neuroscience, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78539, USA;
| | - Andrea Salinas Rodriguez
- Department of Health and Biomedical Sciences, University of Texas Rio Grande Valley, Edinburg, TX 78539, USA;
| | - Maximiliano Arath Morales
- Department of Biology, College of Science, University of Texas Rio Grande Valley, Edinburg, TX 78539, USA;
| | - Xiaoqian Fang
- Department of Neuroscience, School of Medicine, University of Texas Rio Grande Valley, Edinburg, TX 78539, USA;
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2
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Brum FL, Martins GR, Mohana-Borges R, Sant'Ana da Silva A. The acquisition of thin sections of açaí (Euterpe oleracea Mart.) seed with elevated potassium content for molecular mapping by mass spectrometry imaging. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023:e9474. [PMID: 36694976 DOI: 10.1002/rcm.9474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 06/17/2023]
Abstract
RATIONALE Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) of tissues became popular in the last decade. Consequently, adapting sample preparation methods for different materials turned out to be a pivotal step for successful analysis due to the requirement of sample slices of 12-20 μm thickness. However, acquiring thin sections compatible with MALDI-IMS for unusual samples is challenging, as existing histological protocols may not be suitable, thus requiring new methods. Açaí (Euterpe oleracea Mart.) seed is an example of a challenging material due to its toughness and resistance to crack, therefore our goal was to develop a methodology to obtain thin (12-20 μm) and entire sections of açaí seeds for MALDI-IMS analysis. METHODS Different strategies were evaluated for obtaining thin sections of seeds, and the combination of the following steps was found to be the most suitable option: (i) softening of seeds by water immersion for 24 h; (ii) transversal cut of seeds to obtain half-seeds using a razor blade and a hammer; (iii) half-seeds imbibition in gelatin; (iv) samples sectioning using a cryostat at -20°C to obtain samples with 12-20 μm thickness; (v) collection of samples in an indium tin oxide-coated glass slide covered by double-sided copper tape to avoid sample wrapping and ensure adhesion after unfreezing; and (vi) storage of samples in a -80°C freezer, if necessary. RESULTS This adapted sample preparation method enabled the analysis of açaí seeds by MALDI-IMS, providing spatial distribution of carbohydrates in the endosperm. CONCLUSIONS The adaptations developed for sample preparation will help investigate the metabolic and physiological properties of açaí seeds in future studies.
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Affiliation(s)
- Felipe Lopes Brum
- Instituto de Biofísica Carlos Chagas Filho, Centro de Espectrometria de Massas de Biomoléculas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
- Instituto Nacional de Tecnologia, Laboratório de Biocatálise, Rio de Janeiro, RJ, Brazil
| | - Gabriel R Martins
- Instituto Nacional de Tecnologia, Laboratório de Biocatálise, Rio de Janeiro, RJ, Brazil
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Ronaldo Mohana-Borges
- Instituto de Biofísica Carlos Chagas Filho, Centro de Espectrometria de Massas de Biomoléculas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ayla Sant'Ana da Silva
- Instituto Nacional de Tecnologia, Laboratório de Biocatálise, Rio de Janeiro, RJ, Brazil
- Departamento de Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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3
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Chen Y, Li H, Shen Y, Zhang C, Kong X, Li X, Hua Y. Endopeptidases, exopeptidases, and glutamate decarboxylase in soybean water extract and their in vitro activity. Food Chem 2021; 360:130026. [PMID: 34023711 DOI: 10.1016/j.foodchem.2021.130026] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 10/21/2022]
Abstract
The proteolytic activity of some soybean endogenous proteases have been clarified in the previous studies, but the information concerning the roles of these proteases and some other unknown ones during soybean processing are scarce. Herein, 16 endopeptidases, 13 exopeptidases, 24 inhibitors (two serpin-ZX and one subtilisin inhibitor firstly identified), and one glutamate decarboxylase were identified in the soybean water extract by the liquid chromatography tandem mass spectrometry analysis. Amongst the identified endopeptidases, just the aspartic endopeptidases (optimal at pH 2.5-3 and 35-45 °C) showed the detectable proteolytic activity by the tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis and protease inhibitor assay analyses, whereas serine, cysteine, and metallo- endopeptidases (except P34 probable thiol protease) did not. Free amino acid analysis showed that the exopeptidases and glutamate decarboxylase were optimal at pH 6 and 45 °C, and by 6 h incubation, the free amino acids and γ-aminobutyric acid almost doubled.
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Affiliation(s)
- Yeming Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
| | - Huina Li
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Yu Shen
- School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Caimeng Zhang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xiangzhen Kong
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Xingfei Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Yufei Hua
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
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4
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Zhang X, Li H, Lu H, Hwang I. The trafficking machinery of lytic and protein storage vacuoles: how much is shared and how much is distinct? JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3504-3512. [PMID: 33587748 DOI: 10.1093/jxb/erab067] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 02/10/2021] [Indexed: 05/10/2023]
Abstract
Plant cells contain two types of vacuoles, the lytic vacuole (LV) and protein storage vacuole (PSV). LVs are present in vegetative cells, whereas PSVs are found in seed cells. The physiological functions of the two types of vacuole differ. Newly synthesized proteins must be transported to these vacuoles via protein trafficking through the endomembrane system for them to function. Recently, significant advances have been made in elucidating the molecular mechanisms of protein trafficking to these organelles. Despite these advances, the relationship between the trafficking mechanisms to the LV and PSV remains unclear. Some aspects of the trafficking mechanisms are common to both types of vacuole, but certain aspects are specific to trafficking to either the LV or PSV. In this review, we summarize recent findings on the components involved in protein trafficking to both the LV and PSV and compare them to examine the extent of overlap in the trafficking mechanisms. In addition, we discuss the interconnection between the LV and PSV provided by the protein trafficking machinery and the implications for the identity of these organelles.
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Affiliation(s)
- Xiuxiu Zhang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Hui Li
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Hai Lu
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Inhwan Hwang
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- Department of Life Sciences, Pohang University of Science and Technology, 37673 Pohang, South Korea
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5
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Changes in digestibility of proteins from chickpeas (Cicer arietinum L.) germinated in presence of selenium and antioxidant capacity of hydrolysates. Food Chem 2019; 285:290-295. [DOI: 10.1016/j.foodchem.2019.01.137] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/14/2019] [Accepted: 01/20/2019] [Indexed: 11/21/2022]
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6
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Shen W, Yao X, Ye T, Ma S, Liu X, Yin X, Wu Y. Arabidopsis Aspartic Protease ASPG1 Affects Seed Dormancy, Seed Longevity and Seed Germination. PLANT & CELL PHYSIOLOGY 2018; 59:1415-1431. [PMID: 29648652 DOI: 10.1093/pcp/pcy070] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 04/02/2018] [Indexed: 06/08/2023]
Abstract
Seed storage proteins (SSPs) provide free amino acids and energy for the process of seed germination. Although degradation of SSPs by the aspartic proteases isolated from seeds has been documented in vitro, there is still no genetic evidence for involvement of aspartic proteases in seed germination. Here we report that the aspartic protease ASPG1 (ASPARTIC PROTEASE IN GUARD CELL 1) plays an important role in the process of dormancy, viability and germination of Arabidopsis seeds. We show that aspg1-1 mutants have enhanced seed dormancy and reduced seed viability. A significant increase in expression of DELLA genes which act as repressors in the gibberellic acid signal transduction pathway were detected in aspg1-1 during seed germination. Seed germination of aspg1-1 mutants was more sensitive to treatment with paclobutrazol (PAC; a gibberellic acid biosynthesis inhibitor). In contrast, seed germination of ASPG1 overexpression (OE) transgenic lines showed resistant to PAC. The degradation of SSPs in germinating seeds was severely impaired in aspg1-1 mutants. Moreover, the development of aspg1-1 young seedlings was arrested when grown on the nutrient-free medium. Thus ASPG1 is important for seed dormancy, seed longevity and seed germination, and its function is associated with degradation of SSPs and regulation of gibberellic acid signaling in Arabidopsis.
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Affiliation(s)
- Wenzhong Shen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xuan Yao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Tiantian Ye
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Sheng Ma
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiong Liu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaoming Yin
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yan Wu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
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7
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Babst BA, Coleman GD. Seasonal nitrogen cycling in temperate trees: Transport and regulatory mechanisms are key missing links. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 270:268-277. [PMID: 29576080 DOI: 10.1016/j.plantsci.2018.02.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 02/22/2018] [Indexed: 05/08/2023]
Abstract
Nutrient accumulation, one of the major ecosystem services provided by forests, is largely due to the accumulation and retention of nutrients in trees. This review focuses on seasonal cycling of nitrogen (N), often the most limiting nutrient in terrestrial ecosystems. When leaves are shed during autumn, much of the N may be resorbed and stored in the stem over winter, and then used for new stem and leaf growth in spring. A framework exists for understanding the metabolism and transport of N in leaves and stems during winter dormancy, but many of the underlying genes remain to be identified and/or verified. Transport of N during seasonal N cycling is a particularly weak link, since the physical pathways for loading and unloading of amino N to and from the phloem are poorly understood. Short-day photoperiod followed by decreasing temperatures are the environmental cues that stimulate dormancy induction, and nutrient remobilization and storage. However, beyond the involvement of phytochrome, very little is known about the signal transduction mechanisms that link environmental cues to nutrient remobilization and storage. We propose a model whereby nutrient transport and sensing plays a major role in source-sink transitions of leaves and stems during seasonal N cycling.
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Affiliation(s)
- Benjamin A Babst
- Arkansas Forest Resources Center, Division of Agriculture, University of Arkansas System, Monticello, AR 71656, USA; School of Forestry and Natural Resources, University of Arkansas at Monticello, Monticello, AR 71656, USA.
| | - Gary D Coleman
- Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD 20742, USA.
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8
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Wilson KA, Tan-Wilson A. Proteases catalyzing vicilin cleavage in developing pea (Pisum sativum L.) seeds. JOURNAL OF PLANT PHYSIOLOGY 2018; 224-225:86-94. [PMID: 29609123 DOI: 10.1016/j.jplph.2018.03.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 03/07/2018] [Accepted: 03/16/2018] [Indexed: 06/08/2023]
Abstract
Legume species differ in whether or not the 7S globulins stored in seeds undergo proteolytic processing during seed development, while preserving the bicupin structure and trimeric assembly necessary for accumulation and packing into protein storage vacuoles. Two such cleavage sites have been documented for the vicilins in pea cotyledons: one in the linker region between the two cupin domains, and another in an exposed loop in the C-terminal cupin. In this report, we explain the occurrence of vicilin cleavage in developing pea by showing that the storage vacuoles are already acidified before germination, in contrast to soybean and peanut where acidification occurs only after germination. We also show that the two cleavage reactions are catalyzed by two different proteases. The vicilin cleavage at the linker region was inhibited by AEBSF (4-(2-aminoethyl)benzenesulfonyl fluoride), indicative of a serine protease. The cleavage in the C-terminal cupin domain was sensitive to the sulfhydryl-reactive reagents p-chloromercuriphenylsulfonate and iodoacetate, but not to E-64 (N-[N-(L-3-transcarboxyirane-2-carbonyl)-l-leucyl]-agmatine), characteristic of the legumain class of cysteine proteases. During seed development, we found the predominant vicilin cleavage in this pea cultivar (Knight) to be at the site in the second cupin domain; but after germination, both sites were cleaved at about the same rate.
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Affiliation(s)
- Karl A Wilson
- Department of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, United States.
| | - Anna Tan-Wilson
- Department of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, United States.
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9
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AtCAP2 is crucial for lytic vacuole biogenesis during germination by positively regulating vacuolar protein trafficking. Proc Natl Acad Sci U S A 2018; 115:E1675-E1683. [PMID: 29378957 DOI: 10.1073/pnas.1717204115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein trafficking is a fundamental mechanism of subcellular organization and contributes to organellar biogenesis. AtCAP2 is an Arabidopsis homolog of the Mesembryanthemum crystallinum calcium-dependent protein kinase 1 adaptor protein 2 (McCAP2), a member of the syntaxin superfamily. Here, we show that AtCAP2 plays an important role in the conversion to the lytic vacuole (LV) during early plant development. The AtCAP2 loss-of-function mutant atcap2-1 displayed delays in protein storage vacuole (PSV) protein degradation, PSV fusion, LV acidification, and biosynthesis of several vacuolar proteins during germination. At the mature stage, atcap2-1 plants accumulated vacuolar proteins in the prevacuolar compartment (PVC) instead of the LV. In wild-type plants, AtCAP2 localizes to the PVC as a peripheral membrane protein and in the PVC compartment recruits glyceraldehyde-3-phosphate dehydrogenase C2 (GAPC2) to the PVC. We propose that AtCAP2 contributes to LV biogenesis during early plant development by supporting the trafficking of specific proteins involved in the PSV-to-LV transition and LV acidification during early stages of plant development.
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10
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The relationship between vacuolation and initiation of PCD in rice (Oryza sativa) aleurone cells. Sci Rep 2017; 7:41245. [PMID: 28117452 PMCID: PMC5259747 DOI: 10.1038/srep41245] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 12/19/2016] [Indexed: 02/05/2023] Open
Abstract
Vacuole fusion is a necessary process for the establishment of a large central vacuole, which is the central location of various hydrolytic enzymes and other factors involved in death at the beginning of plant programmed cell death (PCD). In our report, the fusion of vacuoles has been presented in two ways: i) small vacuoles coalesce to form larger vacuoles through membrane fusion, and ii) larger vacuoles combine with small vacuoles when small vacuoles embed into larger vacuoles. Regardless of how fusion occurs, a large central vacuole is formed in rice (Oryza sativa) aleurone cells. Along with the development of vacuolation, the rupture of the large central vacuole leads to the loss of the intact plasma membrane and the degradation of the nucleus, resulting in cell death. Stabilizing or disrupting the structure of actin filaments (AFs) inhibits or promotes the fusion of vacuoles, which delays or induces PCD. In addition, the inhibitors of the vacuolar processing enzyme (VPE) and cathepsin B (CathB) block the occurrence of the large central vacuole and delay the progression of PCD in rice aleurone layers. Overall, our findings provide further evidence for the rupture of the large central vacuole triggering the PCD in aleruone layers.
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11
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Wang X, Komatsu S. Improvement of Soybean Products Through the Response Mechanism Analysis Using Proteomic Technique. ADVANCES IN FOOD AND NUTRITION RESEARCH 2017; 82:117-148. [PMID: 28427531 DOI: 10.1016/bs.afnr.2016.12.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Soybean is rich in protein/vegetable oil and contains several phytochemicals such as isoflavones and phenolic compounds. Because of the predominated nutritional values, soybean is considered as traditional health benefit food. Soybean is a widely cultivated crop; however, its growth and yield are markedly affected by adverse environmental conditions. Proteomic techniques make it feasible to map protein profiles both during soybean growth and under unfavorable conditions. The stress-responsive mechanisms during soybean growth have been uncovered with the help of proteomic studies. In this review, the history of soybean as food and the morphology/physiology of soybean are described. The utilization of proteomics during soybean germination and development is summarized. In addition, the stress-responsive mechanisms explored using proteomic techniques are reviewed in soybean.
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Affiliation(s)
- Xin Wang
- National Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan; Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Setsuko Komatsu
- National Institute of Crop Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan; Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
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12
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Natural structural diversity within a conserved cyclic peptide scaffold. Amino Acids 2016; 49:103-116. [PMID: 27695949 DOI: 10.1007/s00726-016-2333-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 09/09/2016] [Indexed: 10/20/2022]
Abstract
We recently isolated and described the evolutionary origin of a diverse class of small single-disulfide bonded peptides derived from Preproalbumin with SFTI-1 (PawS1) proteins in the seeds of flowering plants (Asteraceae). The founding member of the PawS derived peptide (PDP) family is the potent trypsin inhibitor SFTI-1 (sunflower trypsin inhibitor-1) from Helianthus annuus, the common sunflower. Here we provide additional structures and describe the structural diversity of this new class of small peptides, derived from solution NMR studies, in detail. We show that although most have a similar backbone framework with a single disulfide bond and in many cases a head-to-tail cyclized backbone, they all have their own characteristics in terms of projections of side-chains, flexibility and physiochemical properties, attributed to the variety of their sequences. Small cyclic and constrained peptides are popular as drug scaffolds in the pharmaceutical industry and our data highlight how amino acid side-chains can fine-tune conformations in these promising peptides.
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Wilson KA, Chavda BJ, Pierre-Louis G, Quinn A, Tan-Wilson A. Role of vacuolar membrane proton pumps in the acidification of protein storage vacuoles following germination. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 104:242-9. [PMID: 27043965 DOI: 10.1016/j.plaphy.2016.03.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/06/2016] [Accepted: 03/24/2016] [Indexed: 06/05/2023]
Abstract
During soybean (Glycine max (L.) Merrill) seed development, protease C1, the proteolytic enzyme that initiates breakdown of the storage globulins β-conglycinin and glycinin at acidic pH, is present in the protein storage vacuoles (PSVs), the same subcellular compartments in seed cotyledons where its protein substrates accumulate. Actual proteolysis begins to be evident 24 h after seed imbibition, when the PSVs become acidic, as indicated by acridine orange accumulation visualized by confocal microscopy. Imidodiphosphate (IDP), a non-hydrolyzable substrate analog of proton-translocating pyrophosphatases, strongly inhibited acidification of the PSVs in the cotyledons. Consistent with this finding, IDP treatment inhibited mobilization of β-conglycinin and glycinin, the inhibition being greater at 3 days compared to 6 days after seed imbibition. The embryonic axis does not appear to play a role in the initial PSV acidification in the cotyledon, as axis detachment did not prevent acridine orange accumulation three days after imbibition. SDS-PAGE and immunoblot analyses of cotyledon protein extracts were consistent with limited digestion of the 7S and 11S globulins by protease C1 starting at the same time and proceeding at the same rate in detached cotyledons compared to cotyledons of intact seedlings. Embryonic axis removal did slow down further breakdown of the storage globulins by reactions known to be catalyzed by protease C2, a cysteine protease that normally appears later in seedling growth to continue the storage protein breakdown initiated by protease C1.
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Affiliation(s)
- Karl A Wilson
- Department of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, USA.
| | - Burzin J Chavda
- Department of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, USA
| | - Gandhy Pierre-Louis
- Department of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, USA
| | - Adam Quinn
- Department of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, USA
| | - Anna Tan-Wilson
- Department of Biological Sciences, Binghamton University, Binghamton, NY 13902-6000, USA
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Cupincin: A Unique Protease Purified from Rice (Oryza sativa L.) Bran Is a New Member of the Cupin Superfamily. PLoS One 2016; 11:e0152819. [PMID: 27064905 PMCID: PMC4827828 DOI: 10.1371/journal.pone.0152819] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 03/18/2016] [Indexed: 12/03/2022] Open
Abstract
Cupin superfamily is one of the most diverse super families. This study reports the purification and characterization of a novel cupin domain containing protease from rice bran for the first time. Hypothetical protein OsI_13867 was identified and named as cupincin. Cupincin was purified to 4.4 folds with a recovery of 4.9%. Cupincin had an optimum pH and temperature of pH 4.0 and 60°C respectively. Cupincin was found to be a homotrimer, consisting of three distinct subunits with apparent molecular masses of 33.45 kDa, 22.35 kDa and 16.67 kDa as determined by MALDI-TOF, whereas it eluted as a single unit with an apparent molecular mass of 135.33 ± 3.52 kDa in analytical gel filtration and migrated as a single band in native page, suggesting its homogeneity. Sequence identity of cupincin was deduced by determining the amino-terminal sequence of the polypeptide chains and by and de novo sequencing. For understanding the hydrolysing mechanism of cupincin, its three-dimensional model was developed. Structural analysis indicated that cupincin contains His313, His326 and Glu318 with zinc ion as the putative active site residues, inhibition of enzyme activity by 1,10-phenanthroline and atomic absorption spectroscopy confirmed the presence of zinc ion. The cleavage specificity of cupincin towards oxidized B-chain of insulin was highly specific; cleaving at the Leu15-Tyr16 position, the specificity was also determined using neurotensin as a substrate, where it cleaved only at the Glu1-Tyr2 position. Limited proteolysis of the protease suggests a specific function for cupincin. These results demonstrated cupincin as a completely new protease.
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15
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Wilson KA, Tan-Wilson A. Proteolysis of the peanut allergen Ara h 1 by an endogenous aspartic protease. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 96:301-310. [PMID: 26322854 DOI: 10.1016/j.plaphy.2015.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/11/2015] [Accepted: 08/12/2015] [Indexed: 06/04/2023]
Abstract
The 7S and 11S globulins of peanuts are subjected to proteolysis two days after seed imbibition, with Ara h 1 and the arachin acidic chains being among the first storage proteins to be mobilized. Proteolytic activity was greatest at pH 2.6-3 and is inhibited by pepstatin A, characteristic of an aspartic protease. This activity persists in seedling cotyledons up to at least 8 days after imbibition. In vitro proteolysis of Ara h 1 at pH 2.6 by extracts of cotyledons from seedlings harvested 24 h after seed imbibition generates newly appearing bands on SDS-PAGE. Partial sequences of Ara h 1 that were obtained through LC-MS/MS analysis of in-gel trypsin digests of those bands, combined with information on fragment size, suggest that proteolysis begins in the region that links the two cupin domains to produce two 33/34 kD fragments, each one encompassing an intact cupin domain. The later appearance of two 18 and 10/11 kD fragments can be explained by proteolysis within an exposed site in the cupin domains of each of the 33/34 kD fragments. The same or similar proteolytic activity was observed in developing seeds, but Ara h 1 remains intact through seed maturation. This is partly explained by the observation that acidification of the protein storage vacuoles, demonstrated by vacuolar accumulation of acridine orange that was dissipated by a membrane-permeable base, occurs only after germination. These findings suggest a method for use of the seed aspartic protease in reducing peanut allergy due to Ara h 1.
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Affiliation(s)
- Karl A Wilson
- Department of Biological Sciences, State University of New York at Binghamton, Binghamton, NY 13902-6000, USA
| | - Anna Tan-Wilson
- Department of Biological Sciences, State University of New York at Binghamton, Binghamton, NY 13902-6000, USA.
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Preece KE, Drost E, Hooshyar N, Krijgsman A, Cox PW, Zuidam NJ. Confocal imaging to reveal the microstructure of soybean processing materials. J FOOD ENG 2015. [DOI: 10.1016/j.jfoodeng.2014.09.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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17
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Islam N, Li G, Garrett WM, Lin R, Sriram G, Cooper B, Coleman GD. Proteomics of Nitrogen Remobilization in Poplar Bark. J Proteome Res 2014; 14:1112-26. [DOI: 10.1021/pr501090p] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Nazrul Islam
- Department
of Plant Sciences and Landscape Architecture, University of Maryland, College
Park, Maryland 20742, United States
| | - Gen Li
- Department
of Plant Sciences and Landscape Architecture, University of Maryland, College
Park, Maryland 20742, United States
| | - Wesley M. Garrett
- Animal
Biosciences and Biotechnology Laboratory, USDA-ARS, Beltsville, Maryland 20705, United States
| | - Rongshuang Lin
- Department
of Plant Sciences and Landscape Architecture, University of Maryland, College
Park, Maryland 20742, United States
| | - Ganesh Sriram
- Department
of Chemical and Biomolecular Engineering, University of Maryland, College
Park, Maryland 20742, United States
| | - Bret Cooper
- Soybean
Genomics and Improvement Laboratory, USDA-ARS, Beltsville, Maryland 20705, United States
| | - Gary D. Coleman
- Department
of Plant Sciences and Landscape Architecture, University of Maryland, College
Park, Maryland 20742, United States
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Han C, Yin X, He D, Yang P. Analysis of proteome profile in germinating soybean seed, and its comparison with rice showing the styles of reserves mobilization in different crops. PLoS One 2013; 8:e56947. [PMID: 23460823 PMCID: PMC3584108 DOI: 10.1371/journal.pone.0056947] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 01/16/2013] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Seed germination is a complex physiological process during which mobilization of nutrient reserves happens. In different crops, this event might be mediated by different regulatory and metabolic pathways. Proteome profiling has been proved to be an efficient way that can help us to construct these pathways. However, no such studies have been performed in soybean germinating seeds up to date. RESULTS Proteome profiling was conducted through one-dimensional gel electrophoresis followed by liquid chromatography and tandem mass spectrometry strategy in the germinating seeds of soybean (glycine max). Comprehensive comparisons were also carried out between rice and soybean germinating seeds. 764 proteins belonging to 14 functional groups were identified and metabolism related proteins were the largest group. Deep analyses of the proteins and pathways showed that lipids were degraded through lipoxygenase dependent pathway and proteins were degraded through both protease and 26S proteosome system, and the lipoxygenase could also help to remove the reactive oxygen species during the rapid mobilization of reserves of soybean germinating seeds. The differences between rice and soybean germinating seeds proteome profiles indicate that each crop species has distinct mechanism for reserves mobilization during germination. Different reserves could be converted into starches before they are totally utilized during the germination in different crops seeds. CONCLUSIONS This study is the first comprehensive analysis of proteome profile in germinating soybean seeds to date. The data presented in this paper will improve our understanding of the physiological and biochemical status in the imbibed soybean seeds just prior to germination. Comparison of the protein profile with that of germinating rice seeds gives us new insights on mobilization of nutrient reserves during the germination of crops seeds.
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Affiliation(s)
- Chao Han
- Key Laboratory of Plant Germplasm Enhancement and Speciality Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Xiaojian Yin
- Key Laboratory of Plant Germplasm Enhancement and Speciality Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Dongli He
- Key Laboratory of Plant Germplasm Enhancement and Speciality Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
| | - Pingfang Yang
- Key Laboratory of Plant Germplasm Enhancement and Speciality Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
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Babazadeh N, Poursaadat M, Sadeghipour HR, Colagar AHZ. Oil body mobilization in sunflower seedlings is potentially regulated by thioredoxin h. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 57:134-42. [PMID: 22705588 DOI: 10.1016/j.plaphy.2012.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 05/15/2012] [Indexed: 05/11/2023]
Abstract
Thioredoxins are believed to mediate starch and protein mobilization in germinating cereals and dicotyledons. Nothing is known about redox regulation of lipid mobilization in plants. The possible redox regulation by thioredoxin h (Trx h) of a thiol-protease which degrades the oleosin coat of the oil body and its impacts on lipid mobilization was investigated in sunflower (Helianthus annuus L.) seedlings. An alkaline proteolytic activity stimulated by light was detected in seedlings. In vitro, the activity of this alkaline protease increased after reduction by NADPH-thiordoxin reductase system (NTS). The expression pattern of an alkaline 65 kDa thiol protease detected by gelatin SDS-PAGE technique, corresponded to the activity profile of the NTS-activated protease. The thiol-specific fuorochrome monobromobimane (mBBr) showed that a 65 kDa protein was also in a reduced state in vivo and becomes reduced in vitro by NTS. Except for 17-20 kDa oleosins, other oil body associated mBBr-labeled proteins were disappeared within three days following germination. Treatments of sunflower oil bodies by the NTS-activated alkaline protease made them more susceptible to maize lipase action. Ascorbate application enhanced lipid mobilization of seedlings. A model for seedling oil body mobilization was proposed according to which Trx h or other Trx isoforms, reductively activates an oleosin degrading thiol-protease and some oil body proteins, thus renders the organelle more susceptible to subsequent lipolytic actions. For the first time the potential role of Trx in the mobilization of lipid reserves in plants has been shown.
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Affiliation(s)
- Nahid Babazadeh
- Department of Biology, Faculty of Science, Golestan University, Gorgan, Iran
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20
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Abstract
The mobilization of seed storage proteins upon seed imbibition and germination is a crucial process in the establishment of the seedling. Storage proteins fold compactly, presenting only a few vulnerable regions for initial proteolytic digestion. Evolutionarily related storage proteins have similar three-dimensional structure, and thus tend to be initially cleaved at similar sites. The initial cleavage makes possible subsequent rapid and extensive breakdown catalyzed by endo- and exopeptidases. The proteolytic enzymes that degrade the storage proteins during mobilization identified so far are mostly cysteine proteases, but also include serine, aspartic and metalloproteases. Plants often ensure early initiation of storage protein mobilization by depositing active proteases during seed maturation, in the very compartments where storage proteins are sequestered. Various means are used in such cases to prevent proteolytic attack until after imbibition of the seed with water. This constraint, however, is not always enforced as the dry seeds of some plant species contain proteolytic intermediates as a result of limited proteolysis of some storage proteins. Besides addressing fundamental questions in plant protein metabolism, studies of the mobilization of storage proteins will point out proteolytic events to avoid in large-scale production of cloned products in seeds. Conversely, proteolytic enzymes may be applied toward reduction of food allergens, many of which are seed storage proteins.
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Affiliation(s)
- Anna L Tan-Wilson
- Department of Biological Sciences, State University of New York at Binghamton, Binghamton, NY 13902, USA.
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21
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Tan-Wilson A, Bandak B, Prabu-Jeyabalan M. The PA domain is crucial for determining optimum substrate length for soybean protease C1: structure and kinetics correlate with molecular function. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 53:27-32. [PMID: 22285412 DOI: 10.1016/j.plaphy.2012.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 01/03/2012] [Indexed: 05/31/2023]
Abstract
A subtilisin-like enzyme, soybean protease C1 (EC 3.4.21.25), initiates the degradation of the β-conglycinin storage proteins in early seedling growth. Previous kinetic studies revealed a nine-residue (P5-P4') length requirement for substrate peptides to attain optimum cleavage rates. This modeling study used the crystal structure of tomato subtilase (SBT3) as a starting model to explain the length requirement. The study also correlates structure to kinetic studies that elucidated the amino acid preferences of soybean protease C1 for P1, P1' and P4' locations of the cleavage sequence. The interactions of a number of protease C1 residues with P5, P4 and P4' residues of its substrate elucidated by this analysis can explain why the enzyme only hydrolyzes peptide bonds outside of soybean storage protein's core double β-barrel cupin domains. The findings further correlate with the literature-reported hypothesis for the subtilisin-specific protease-associated (PA) domain to play a critical role. Residues of the SBT3 PA domain also interact with the P2' residue on the substrate's carboxyl side of the scissile bond, while those on protease C1 interact with its substrate's P4' residue. This stands in contrast with the subtilisin BPN' that has no PA domain, and where the enzyme makes stronger interaction with residues on the amino side of the cleaved bond. The variable patterns of interactions between the substrate models and PA domains of tomato SBT3 and soybean protease C1 illustrate a crucial role for the PA domain in molecular recognition of their substrates.
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Affiliation(s)
- Anna Tan-Wilson
- Department of Biological Sciences, State University of New York at Binghamton, 4400 Vestal Parkway East, Binghamton, NY 13902, USA
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22
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Baranova EN, Gulevich AA, Kalinina-Turner EB, Koslov NN. Effects of NaCl, Na2SO4 and mannitol on utilization of storage protein and transformation of vacuoles in the cotyledons and seedling roots of alfalfa (Medicago sativa L.). ACTA ACUST UNITED AC 2011. [DOI: 10.3103/s1068367411010034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Zheng H, Staehelin LA. Protein storage vacuoles are transformed into lytic vacuoles in root meristematic cells of germinating seedlings by multiple, cell type-specific mechanisms. PLANT PHYSIOLOGY 2011; 155:2023-35. [PMID: 21278307 PMCID: PMC3091105 DOI: 10.1104/pp.110.170159] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 01/24/2011] [Indexed: 05/18/2023]
Abstract
We have investigated the structural events associated with vacuole biogenesis in root tip cells of tobacco (Nicotiana tabacum) seedlings preserved by high-pressure freezing and freeze-substitution techniques. Our micrographs demonstrate that the lytic vacuoles (LVs) of root tip cells are derived from protein storage vacuoles (PSVs) by cell type-specific sets of transformation events. Analysis of the vacuole transformation pathways has been aided by the phytin-dependent black osmium staining of PSV luminal contents. In epidermal and outer cortex cells, the central LVs are formed by a process involving PSV fusion, storage protein degradation, and the gradual replacement of the PSV marker protein α-tonoplast intrinsic protein (TIP) with the LV marker protein γ-TIP. In contrast, in the inner cortex and vascular cylinder cells, the transformation events are more complex. During mobilization of the stored molecules, the PSV membranes collapse osmotically upon themselves, thereby squeezing the vacuolar contents into the remaining bulging vacuolar regions. The collapsed PSV membranes then differentiate into two domains: (1) vacuole "reinflation" domains that produce pre-LVs, and (2) multilamellar autophagosomal domains that are later engulfed by the pre-LVs. The multilamellar autophagosomal domains appear to originate from concentric sheets of PSV membranes that create compartments within which the cytoplasm begins to break down. Engulfment of the multilamellar autophagic vacuoles by the pre-LVs gives rise to the mature LVs. During pre-LV formation, the PSV marker α-TIP disappears and is replaced by the LV marker γ-TIP. These findings demonstrate that the central LVs of root cells arise from PSVs via cell type-specific transformation pathways.
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Affiliation(s)
- Huiqiong Zheng
- Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.
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24
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Khan S, Verma G, Sharma S. A novel Ca2+-activated protease from germinating Vigna radiata seeds and its role in storage protein mobilization. JOURNAL OF PLANT PHYSIOLOGY 2010; 167:855-861. [PMID: 20149479 DOI: 10.1016/j.jplph.2010.01.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2009] [Revised: 01/20/2010] [Accepted: 01/20/2010] [Indexed: 05/28/2023]
Abstract
Calcium (Ca(2+))-dependent/activated proteases make decisive cleavages in proteins, affecting their further degradation/activation. Few such Ca(2+)-dependent proteases have been reported from plants, and none during germination-related events. Seeds are woken up from their quiescent state upon imbibition of water. The subsequent process of germination is strongly influenced by hormones (mainly gibberellins) and light, with both resulting in change in intracellular Ca(2+). We have investigated the effect of Ca(2+) on protease activity in extracts prepared from dry Vigna radiata (L.) Wilczec seeds and cotyledons 4, 24, 48 and 72h post-imbibition. Ca(2+)-activated protease activity is present at a very low level in dry seeds, rises with imbibition and peaks 24h post-imbibition. Subsequently, the activity rapidly declines, even as total protease activity continues to rise. Calcium activation of proteolysis was reversed by ethylene diamine tetraacetic acid (EDTA), ethylene glycol-bis (2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA), 1,10, phenanthroline, chlorpromazine and by beta-mercaptoethanol in a concentration-dependent manner. Protease activity was also inhibited by para chloro mercuribenzoate (pCMB) and l-trans-epoxysuccinyl-leucylamido(4-guanidino) butane (E 64), while phenyl methyl sulfonyl fluoride (PMSF) and pepstatin did not effect Ca(2+) activation. The protease could be separated from the calmodulin fraction by size-exclusion chromatography, while retaining its ability for Ca(2+) activation, excluding the possibility of activation through calmodulin-based pathways. The presence of a Ca(2+)-activated protease in the cotyledons suggests its role in a predetermined program of germination involving elevation of cytosolic Ca(2+) levels during germination. This protease could be an important enzyme interfacing cytoplasmic signaling events and initiation of storage protein mobilization during seed germination.
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Affiliation(s)
- Sadaf Khan
- Department of Biochemistry, Lucknow University, Lucknow 226007, India
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25
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Jinka R, Ramakrishna V, Rao SK, Rao RP. Purification and characterization of cysteine protease from germinating cotyledons of horse gram. BMC BIOCHEMISTRY 2009; 10:28. [PMID: 19919695 PMCID: PMC2784799 DOI: 10.1186/1471-2091-10-28] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2009] [Accepted: 11/17/2009] [Indexed: 11/10/2022]
Abstract
Background Proteolytic enzymes play central role in the biochemical mechanism of germination and intricately involved in many aspects of plant physiology and development. To study the mechanism of protein mobilization, undertaken the task of purifying and characterizing proteases, which occur transiently in germinating seeds of horse gram. Results Cysteine protease (CPRHG) was purified to homogeneity with 118 fold by four step procedure comprising Crude extract, (NH4)2SO4 fractionation, DEAE-Cellulose and CM-sephacel chromatography from the 2 day germinating cotyledons of horse gram (Macrotyloma uniflorum (Lam.) Verdc.). CPRHG is a monomer with molecular mass of 30 k Da, was determined by SDS-PAGE and gel filtration. The purified enzyme on IEF showed two isoforms having pI values of 5.85 and 6.1. CPRHG composed of high content of aspartic acid, glutamic acid and serine. The enzyme activity was completely inhibited by pCMB, iodoacetate and DEPC indicating cysteine and histidine residues at the active site. However, on addition of sulfhydryl reagents (cysteine, dithiothreitol, glutathione and beta-ME) reverse the strong inhibition by pCMB. The enzyme is fairly stable toward pH and temperature. Immunoblot analysis shows that the enzyme synthesized as zymogen (preproenzyme with 81 kDa) and processed to a 40 kDa proenzyme which was further degraded to give 30 kDa active enzyme. Conclusion It appears that the newly synthesized protease is inactive, and activation takes place during germination. CPRHG has a broad substrate specificity and stability in pH, temperature, etc. therefore, this protease may turn out to be an efficient choice for the pharmaceutical, medicinal, food, and biotechnology industry.
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Affiliation(s)
- Rajeswari Jinka
- Center for Cellular and Molecular Biology, Uppal Road, Hyderabad - 500 007, India.
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26
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Ramakrishna V, Rajasekhar S, Reddy LS. Identification and purification of metalloprotease from dry grass pea (Lathyrus sativus L.) seeds. Appl Biochem Biotechnol 2009; 160:63-71. [PMID: 19156362 DOI: 10.1007/s12010-009-8523-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Accepted: 01/05/2009] [Indexed: 01/09/2023]
Abstract
Proteolytic enzymes play a central role in the biochemical mechanism of germination. The present study reported the presence of Zn(2+)-dependent endoproteases in the dry seeds of grass pea (Lathyrus sativus L.) with maximum caseinolytic activity observed at pH 8.0. Studies with class-specific inhibitors (specific for cysteine, serine, aspartate, and metalloproteases) on crude extract identified the inhibitory effect of 1,10-phenanthroline. This inhibitory effect was overcome by addition of Zn(2+), not with Fe, Ca, Cu, Mg, or Co and indicates that the protease is Zn(2+) dependent. This metalloprotease was further characterized by attempting gelatin-PAGE zymography and observed three distinct zones of proteolytic activity with higher mobility. The protease fraction consisted of three isoforms as evidenced by the appearance of three different bands on gelatin-PAGE zymogram. We also purified these proteases to 110-fold by a three-step procedure comprising crude extract from dry seeds, (NH(4))(2)SO(4) fractionation, and casein-alginate affinity chromatography. The molecular mass of isoforms of metalloproteases is 25, 18, and 14 kDa.
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Affiliation(s)
- Vadde Ramakrishna
- Department of Biotechnology, Sri Krishnadevaraya University, Andhra Pradesh, India.
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27
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Li M, Wan WN, Petrova O, Huang F, Zhou Z, Boyd P, Wilson KA, Tan-Wilson A. Applicability of multigene family-specific antibodies toward studies of the subtilases in Arabidopsis thaliana. Anal Biochem 2009; 384:114-22. [DOI: 10.1016/j.ab.2008.09.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 09/04/2008] [Accepted: 09/10/2008] [Indexed: 01/06/2023]
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28
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Tsuji A, Kikuchi Y, Ogawa K, Saika H, Yuasa K, Nagahama M. Purification and characterization of cathepsin B-like cysteine protease from cotyledons of daikon radish, Raphanus sativus. FEBS J 2008; 275:5429-43. [PMID: 18959767 DOI: 10.1111/j.1742-4658.2008.06674.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Plant cathepsin B-like cysteine protease (CBCP) plays a role in disease resistance and in protein remobilization during germination. The ability of animal cathepsin B to function as a dipeptidyl carboxypeptidase has been attributed to the presence of a dihistidine (His110-His111) motif in the occluding loop, which represents a unique structure of cathepsin B. However, a dihistidine motif is not present in the predicted sequence of the occluding loop of plant CBCP, as determined from cDNA sequence analysis, and the loop is shorter. In an effort to investigate the enzymatic properties of plant CBCP, which possesses the unusual occluding loop, we have purified CBCP from the cotyledons of daikon radish (Raphanus sativus) by chromatography through Sephacryl S-200, DEAE-cellulose, hydroxyapatite and organomercurial-Sepharose. The molecular mass of the enzyme was estimated to be 28 kDa by SDS/PAGE under reducing conditions. The best synthetic substrate for CBCP was t-butyloxycarbonyl Leu-Arg-Arg-4-methylcoumaryl 7-amide, as is the case with human cathepsin B. However, the endopeptidase activity of CBCP towards glucagon and adrenocorticotropic hormone showed broad cleavage specificity. Human cathepsin B preferentially cleaves model peptides via its dipeptidyl carboxypeptidase activity, whereas daikon CBCP displays both endopeptidase and exopeptidase activities. In addition, CBCP was found to display carboxymonopeptidase activity against the substrate o-aminobenzoyl-Phe-Arg-Phe(4-NO(2)). Daikon CBCP is less sensitive (1/7000) to CA-074 than human cathepsin B. Expression analysis of CBCP at the protein and RNA levels indicated that daikon CBCP activity in cotyledons is regulated by post-transcriptional events during germination.
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Affiliation(s)
- Akihiko Tsuji
- Department of Biological Science and Technology, University of Tokushima Graduate School, Japan.
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29
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Blöchl A, Peterbauer T, Hofmann J, Richter A. Enzymatic breakdown of raffinose oligosaccharides in pea seeds. PLANTA 2008; 228:99-110. [PMID: 18335235 DOI: 10.1007/s00425-008-0722-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Accepted: 02/26/2008] [Indexed: 05/26/2023]
Abstract
Both alkaline and acidic alpha-galactosidases (alpha-D: -galactoside galactohydrolases, E.C.3.2.1.22) isolated from various plant species have been described, although little is known about their co-occurrence and functions in germinating seeds. Here, we report on the isolation of two cDNAs, encoding for alpha-galactosidases from maturing and germinating seeds of Pisum sativum. One was identified as a member of the acidic alpha-galactosidase of the family 27 glycosyl hydrolase cluster and the other as a member of the family of alkaline alpha-galactosidases, which are highly homologous to seed imbibition proteins (SIPs). PsGAL1 transcripts, encoding for the ACIDIC alpha-GALACTOSIDASE, were predominately expressed during seed maturation and acidic enzyme activities were already present in dry seeds, showing little changes during seed germination. Compartmentation studies revealed that acidic alpha-galactosidases were located in protein storage vacuoles (PSVs). PsAGA1, encoding for the ALKALINE alpha-GALACTOSIDASE, was only expressed after radicle protrusion, when about 50% of RFOs have already been broken down. RFO breakdown was markedly decreased when the translation of the alkaline enzyme was inhibited, providing evidence that PsAGA1 indeed functioned in RFO degradation. Based on these data, we present an integrated model of RFO breakdown by two sequentially active alpha-galactosidases in pea seeds.
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Affiliation(s)
- Andreas Blöchl
- Department of Chemical Ecology and Ecosystem Research, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
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30
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Winter N, Kollwig G, Zhang S, Kragler F. MPB2C, a microtubule-associated protein, regulates non-cell-autonomy of the homeodomain protein KNOTTED1. THE PLANT CELL 2007; 19:3001-18. [PMID: 17965274 PMCID: PMC2174720 DOI: 10.1105/tpc.107.044354] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 08/30/2007] [Accepted: 10/06/2007] [Indexed: 05/18/2023]
Abstract
Plasmodesmata establish a pathway for the intercellular trafficking of viral movement proteins and endogenous non-cell-autonomous proteins, such as the two closely related meristem-maintaining KNOTTED1-like homeobox (KNOX) proteins Zea mays KNOTTED1 (KN1) and Arabidopsis thaliana SHOOTMERISTEMLESS (STM). KNOX family members are DNA binding proteins that regulate the transcriptional activity of target genes in conjunction with BEL1-like homeodomain proteins. It has been shown previously, using in vivo transport assays, that the C-terminal domain of KN1, including the homeodomain, is necessary and sufficient for cell-to-cell transport through plasmodesmata. Here, using interaction and coexpression assays, we demonstrate that the microtubule-associated and viral movement protein binding protein MPB2C from Nicotiana tabacum, and its homolog in Arabidopsis, At MPB2C, are KN1/STM binding factors. Interaction between the MPB2C proteins and KN1/STM was mapped to the KN1 homeodomain, a region not essential for heterodimerization with BEL1. Expression of MPB2C in single cells prevented KN1 cell-to-cell movement. Furthermore, in vivo trichome rescue studies established that MPB2C negatively regulates KN1 association to plasmodesmata and, consequently, cell-to-cell transport. These findings are discussed in terms of the role played by MPB2C proteins in regulating the cell-to-cell trafficking of homeodomain proteins in plants.
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Affiliation(s)
- Nikola Winter
- Department of Biochemistry, University of Viena, Viena A-1030, Austria
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31
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Hinz G, Colanesi S, Hillmer S, Rogers JC, Robinson DG. Localization of vacuolar transport receptors and cargo proteins in the Golgi apparatus of developing Arabidopsis embryos. Traffic 2007; 8:1452-64. [PMID: 17696967 DOI: 10.1111/j.1600-0854.2007.00625.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Using immunogold electron microscopy, we have investigated the relative distribution of two types of vacuolar sorting receptors (VSR) and two different types of lumenal cargo proteins, which are potential ligands for these receptors in the secretory pathway of developing Arabidopsis embryos. Interestingly, both cargo proteins are deposited in the protein storage vacuole, which is the only vacuole present during the bent-cotyledon stage of embryo development. Cruciferin and aleurain do not share the same pattern of distribution in the Golgi apparatus. Cruciferin is mainly detected in the cis and medial cisternae, especially at the rims where storage proteins aggregate into dense vesicles (DVs). Aleurain is found throughout the Golgi stack, particularly in the trans cisternae and trans Golgi network where clathrin-coated vesicles (CCVs) are formed. Nevertheless, aleurain was detected in both DV and CCV. VSR-At1, a VSR that recognizes N-terminal vacuolar sorting determinants (VSDs) of the NPIR type, localizes mainly to the trans Golgi and is hardly detectable in DV. Receptor homology-transmembrane-RING H2 domain (RMR), a VSR that recognizes C-terminal VSDs, has a distribution that is very similar to that of cruciferin and is found in DV. Our results do not support a role for VSR-At1 in storage protein sorting, instead RMR proteins because of their distribution similar to that of cruciferin in the Golgi apparatus and their presence in DV are more likely candidates. Aleurain, which has an NPIR motif and seems to be primarily sorted via VSR-At1 into CCV, also possesses putative hydrophobic sorting determinants at its C-terminus that could allow the additional incorporation of this protein into DV.
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Affiliation(s)
- Giselbert Hinz
- Department of Cell Biology, Heidelberg Institute for Plant Sciences, University of Heidelberg, 69120 Heidelberg, Germany
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